What is a Version 4 UUID and how is it generated?

A Version 4 UUID is a 128-bit identifier generated from pseudo-random numbers. Out of the 128 bits, 6 bits are reserved for version and variant metadata, leaving 122 bits of pure cryptographic entropy.

Can two generated UUIDs ever collide?

In practical terms, no. Generating 1 billion UUIDs every second for 100 years would yield only a 50% probability of a single collision. The odds are astronomically negligible.

Is it safe to generate UUIDs in the browser?

Yes. BrowserTools uses window.crypto.getRandomValues(), which sources hardware entropy directly from your operating system kernel. No identifiers are transmitted to our servers.

How does Random UUID Generator work without uploading my data?

Random UUID Generator runs entirely inside your browser's sandbox: the page loads once, and every operation after that executes on your own device's CPU. No input, file, or result is transmitted to any server — you can even watch the network tab stay silent while you use it.

Random UUID Generator

Bulk UUID v4 identifiers, copy-ready

Free Private No uploads

UUID v4

How many?

1–1000

Format

10 UUIDs (RFC 4122 v4)

9aa6f00b-c0c0-406a-859c-b5d17510c70a 91af4654-2196-4451-9979-1041fe39a762 de73532c-1dec-4e37-8296-62de52c89eb2 81f3c8a4-38b4-4a43-b438-cf300db2f9c8 b6c10acb-861f-4425-bbaa-63a3d780ad68 96a5282c-9f07-4e85-baeb-79f0913b826d 1b3eb5c5-ec1d-448c-9f0f-bfc1f57793d1 606a4b5f-6ef9-4e25-82ec-848182e44bea dfafb211-c560-4c9b-9e1b-4e81e8f1cee5 b387fab0-cd1f-445e-9c0a-e011f34b774e

100% Private & In-Browser

Processed locally using client-side JavaScript. Your files and data never touch any server.

Instant & Unlimited

No registration, no waiting queues, and no limits on file conversions or generations.

Tool Overview & Guide

What is Random UUID Generator?

The Random UUID Generator produces cryptographically random, RFC 4122-compliant Version 4 Universally Unique Identifiers (UUIDs). Powered by the browser's native Web Crypto API (crypto.getRandomValues), each 128-bit identifier contains 122 bits of high-entropy randomness, resulting in a collision probability so vanishingly small (1 in 2.71 × 10^36) that it is virtually impossible for duplicates to occur.

Step-by-Step Instructions

How to use Random UUID Generator

Select your required quantity of UUIDs (from 1 up to 10,000 in a single batch).

Choose formatting options: standard hyphenated, uppercase, braced ({uuid}), or compact unhyphenated.

The browser's Web Crypto CSPRNG fills 16-byte buffers and sets the version (0100) and variant (10) bits locally.

Copy all generated UUIDs to your clipboard or download them as a clean text file.

Key Capabilities

100% RFC 4122 Version 4 compliant output
Powered by cryptographic Web Crypto API — zero pseudo-random math
Bulk generation up to 10,000 UUIDs in milliseconds
Flexible formatting: hyphenated, uppercase, braced, and comma-separated exports

Common Use Cases

Seeding primary keys in distributed SQL and NoSQL databases (PostgreSQL, MongoDB, CockroachDB).
Generating unique transaction IDs, correlation IDs, and idempotent request tokens for REST and GraphQL APIs.
Creating reproducible test fixtures and mock datasets for automated test suites.
Assigning globally distinct identifiers to files, user sessions, and telemetry events.

Clear Answers

Frequently Asked Questions

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